Related Experiment Video
Updated: Jun 17, 2026
08:17
Inducing Complete Polyp Regeneration from the Aboral Physa of the Starlet Sea Anemone Nematostella vectensis
Published on: January 14, 2017
Autophagy and apoptosis in planarians.
Cristina González-Estévez1, Emili Saló
1Institute of Genetics, Queen's Medical Centre, The University of Nottingham, UK.
Apoptosis : an International Journal on Programmed Cell Death
|January 14, 2010
Summary
Planarians exhibit remarkable regeneration and body remodeling, shrinking during starvation and regrowing all tissues, including reproductive organs. This plasticity highlights the role of neoblasts (somatic stem cells) in adaptation and repair.
Area of Science:
- Developmental Biology
- Cell Biology
- Regenerative Medicine
Background:
- Planarians possess exceptional regenerative and body remodeling capabilities, adapting to starvation by shrinking and later restoring all tissues.
- These flatworms are classic models for studying stem cells and regeneration due to their plasticity.
- Shrinkage involves the digestion of non-essential tissues, while regrowth restores reproductive structures.
Purpose of the Study:
- To review current understanding and hypotheses on apoptosis and autophagy in planarian regeneration.
- To highlight the roles of these processes in adaptation to environmental stress.
- To emphasize the importance of studying apoptosis and autophagy alongside neoblast biology.
Main Methods:
- Literature review of studies on planarian regeneration, stem cells, and cellular processes.
- Synthesis of existing data on morphallaxis, neoblasts, proliferation, differentiation, apoptosis, and autophagy.
- Hypothesizing the involvement and regulation of apoptosis and autophagy in planarian adaptation.
Main Results:
- Planarian adaptation (morphallaxis) involves orchestrated proliferation, differentiation, apoptosis, and autophagy.
- Neoblasts, comprising 20-30% of parenchyma cells, are key somatic stem cells driving tissue turnover and regeneration.
- While neoblast function is well-studied, the specific roles and timing of apoptosis and autophagy in planarian adaptation remain less understood.
Conclusions:
- Apoptosis and autophagy are crucial, yet understudied, processes in planarian adaptation and regeneration.
- Further research into apoptosis and autophagy is essential for a complete understanding of planarian plasticity.
- Investigating these cellular mechanisms will advance regenerative medicine and stem cell biology.
Related Concept Videos
01:22Cellular Injury V: Apoptosis and Autophagy
Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...
01:18Autophagic Cell Death
Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
01:30Apoptosis
Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
01:17Phagocytosis of Apoptotic Cells
Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or immature dendritic cells. Non-professional phagocytes such as epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
01:30Overview of Cell Death
Cell death is an essential process where the body gets rid of old or damaged cells. Cell proliferation and death need to be balanced, as an imbalance between the two may lead to cancer or autoimmune diseases.
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
01:33Whole Body Regeneration
Regeneration is the process of restoring injured or lost tissues, organs, or body parts. While simpler organisms generally show greater ability to regenerate their whole body, few complex animals show similarly exceptional regeneration. For example, planarian flatworms have a unique regenerative potential making them a popular study organism among biologists to understand the mechanisms of whole body regeneration. Other organisms, such as hydra, also show extreme regeneration potential; even...